Integrated circuits comprise multiple layers of materials deposited by various techniques, including chemical vapor deposition. As such, the deposition of materials on a semiconductor substrate via chemical vapor deposition, or CVD, is a critical step in the process of producing integrated circuits. Typical CVD chambers may have a heated substrate support for heating a substrate during processing, a gas port for introducing process gases into the chamber, and a pumping port for maintaining the processing pressure within the chamber and to remove excess gases or processing by products. The inventors have observed that, due to the flow pattern of the gases introduced into the process chamber towards the pumping port, it is difficult to maintain a uniform deposition profile on the substrate. In addition, variance in the emissivity of the internal chamber components leads to non-uniform heat distribution profiles within the chamber and, therefore, on the substrate. Also, thermal non-uniformity is also caused by the typical non-symmetric design of the chamber (for example, one side includes a slit valve for entry and removal of a substrate, and the pumping port is typically disposed on an opposite side of the chamber). The inventors have further observed that such non uniformities in the heat distribution profile across the surface of the substrate further leads to non-uniformities in the deposition of materials on the substrate. This, in turn, leads to further costs incurred in planarizing or otherwise repairing the substrate prior to further processing or possible failure of the integrated circuit all together.
As such, the inventors have provided an improved apparatus for uniformly depositing materials on substrates in a CVD chamber.